Anorexia Nervosa (AN) is a serious psychological condition with a prevalence estimated at 0.48% among adolescent females between 15-19 years. In adolescents, the illness severely affects physical, emotional, and social development. To date, there are no large-scale treatment studies of adolescents with AN. Smaller scale studies, however, suggest that a specific type of family-based treatment (FT) is an effective approach to adolescent onset AN. This multi-site study aims to compare this specific family therapy (FBT) with ego oriented individual psychotherapy (EOIT) to determine which treatment is more efficacious. The study has two specific aims: (1) To compare the relative efficacy of FBT and EOIT in adolescents with AN. We will specifically examine weight gain, psychological concerns about weight and shape and changes in family functioning. (2) To examine potential predictors, mediators and moderators of outcome. To accomplish these aims the following study is proposed: at two centers (60 per center), 120 adolescents between the ages of 12-18 meeting DSM-IV criteria for AN will be randomly assigned to one of two treatment groups: 1) FBT (manualized) for 24 planned patient hours for 12 months; or 2) EOIT (manualized) for 24 planned patient hours over 12 months. All patients will be followed for 1 year after the end of treatment. Assessment will occur at baseline, end of treatment, and six months and one-year follow-up. Primary outcome will be weight change. Secondary outcomes will be changes in weight and shape concerns as measured by the Eating Disorder Examination.